In today's world, many devices have been developed to rely upon wireless transfer of information, particularly via radio-frequency (RF) transmissions. For example, some devices are configured to make decisions whether and how to perform a function based on transmitted information such as authentication information that facilitates the verification of an operator's identity and/or the presence of an authorized user. One such device is an automatic remote and/or keyless entry system for an automobile. Another is a remote starter for a vehicle. Still another is a key fob for enabling access to a computer network.
In such systems, an operator or other user requests commencement of a desired process by performing an initiating step. For example, a user might press a button on a key fob configured for unlocking or opening a vehicle door, for starting a vehicle's engine, for accessing a computer system, or opening a garage door. Alternatively, a user might pull on a door handle of the vehicle or might press an ignition/start button on the vehicle instrument panel. In response, an authorization module having the ability to facilitate commencement of the process (e.g., by facilitating the unlocking or opening the vehicle door, starting of the vehicle's engine, permitting access to the computer system, or opening the garage door) may seek to verify that the request is authorized (i.e., may seek to authenticate the request).
To facilitate an authentication process, the user may carry a security token (e.g., a key fob) configured for transmitting or otherwise providing information, including the authentication information. Just as physical keys have traditionally served to provide physical access to locked objects and places, key fobs, smart cards, radio-frequency identification (RFID) tags, and other similar security tokens are now serving to selectively provide access not only to secured objects and places of a physical nature, but also to communication networks and other services (e.g., financial services, information services). In some cases, security tokens may facilitate multiple-factor authentication such as where the presence of the device and the entry of one or more additional piece of information (e.g., a pin number or password, fingerprints or other biometric information, information transmitted from an alcohol-sensing breath tester, etc.) are required.
To render the use of such security tokens practical, they are typically configured to communicate wirelessly with the secured device. In some cases, a secured device and an associated security token may be configured to communicate via sound or light transmissions. More typically, however, the devices communicate via radio-frequency (i.e., RF) transmissions. Unfortunately, wireless transmissions can be susceptible to jamming such as by interference caused by the presence of competing in-band transmissions. For example, competing transmission of light, sound, and/or electromagnetic signals can interfere with (i.e., jam) the reception and/or interpretation of transmissions intended for elements of a particular system. Sources of potentially-interfering ambient transmissions can include a wide variety of stationary or mobile sources. Sometimes, the sources do not operate on a constant basis. As a result, the jamming caused by such sources may cause only sporadic interference with authentication transmissions, rendering the potentially-interfering ambient transmissions difficult to recognize or characterize.
In a secured device configured for use with a security token, a module configured for facilitating authentication (i.e., an authentication module) may fail to detect the presence of the security token in the presence of an interfering or jamming transmission. This can be particularly problematic where the environment in which the authorization module operates undergoes frequent changes. For example, in an automobile equipped with a remote keyless entry (RKE) system or a passive entry/passive start (PEPS) system, the transmissions present in the ambient environment likely change as the location of the vehicle changes. When a vehicle operator attempts to access or start the vehicle's engine in the presence of a potentially-interfering ambient transmission, the authorization module may be unable to authenticate the operator's request; instead displaying a message indicating that no security token is detected. While back-up systems may be available, many vehicle operators do not know of their existence and/or how to use them. Accordingly, such customers may become frustrated and dissatisfied and may seek to have their vehicles towed (or other systems returned) to a depot for repairs. When the jamming transmission is no longer present, the system resumes functioning properly, thereby hampering identification of the source of the problem and further irritating the operator of the system or others.
Accordingly, it is desirable to provide a system and method for authenticating a request for access to a secured system, wherein the system is configured for use with a security token.